High-resolution cavity ring-down study of acetylene between 12260 and 12380 cm(-1)

The cavity ring-down laser method using a continuously tunable titanium:sap phire ring laser with an external high-finesse cavity has been used to reco rd a high-resolution overtone spectrum of a gaseous (C2H2)-C-12 sample in t he wavenumber region 12260-12380 cm(-1). A direct non-linear least-squares fitting of the ring-down signal is found to lead to increased sensitivity w hen compared with the linear least-squares methods. Two new bands have been observed and rotationally analysed. A comparison of the new results with p revious theoretical work shows a good agreement. (C) 2001 Elsevier Science B.V. All rights reserved.